A pseudo-triatomic model for the analysis of metal–lingand force constants

The diagonal elements of the stretching force-constant matrix have been evaluated for some linear XYZ molecules as a function of the off-diagonal element kXY, YZ. This is used to provide a basis for the comparison of bond strengths in related molecules. The treatment is extended by use of a pseudo-triatomic model to evaluate the force constants of carbonyl, nitrosyl, and cyanide ligands and metal–ligands constants in and metal complexes. The reliability of relatives orders of cis- and trans-ligand effects deduced only from vibration frequencies in examined.